HR: 0800h
AN: SM31B-1233    [Abstracts]
TI: Convection electric field in the near-Earth tail during the super magnetic storm on November 20-21, 2003
AU: * Hori, T
EM: horit@nict.go.jp
AF: National Institute of Information and Communication Technologies, 4-2-1 Nukui-Kita-Machi, Koganei, Tokyo, 184-8795 Japan
AU: Lui, A T
EM: tony.lui@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723-6099 United States
AU: Ohtani, S
EM: shin.ohtani@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723-6099 United States
AU: Mauk, B H
EM: barry.mauk@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723-6099 United States
AU: McEntire, R W
EM: richard.mcentire@jhuapl.edu
AF: National Institute of Information and Communication Technologies, 4-2-1 Nukui-Kita-Machi, Koganei, Tokyo, 184-8795 Japan
AU: Maezawa, K
EM: maezawa@stp.isas.jaxa.jp
AF: Japan Aerospace Exploration Agency/Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa, 229-8510 Japan
AU: Mukai, T
EM: mukai@stp.isas.jaxa.jp
AF: Japan Aerospace Exploration Agency/Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa, 229-8510 Japan
AU: Kasaba, Y
EM: kasaba@stp.isas.jaxa.jp
AF: Japan Aerospace Exploration Agency/Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa, 229-8510 Japan
AU: Hayakawa, H
EM: hayakawa@stp.isas.jaxa.jp
AF: Japan Aerospace Exploration Agency/Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa, 229-8510 Japan
AB: We have examined the electric field observations made by the Geotail spacecraft in the near-Earth magnetotail during the intense magnetic storm that occurred on November 20-21, 2003. The solar wind observation obtained by the ACE spacecraft shows the encounter of a shock-like change in the solar wind/IMF parameters at about 07:30 UT on November 20, 2003, which is followed by an intense southward dip of IMF (-50 nT $<$ IMF-Bz $<$ -20 nT) lasting until the end of the day. On the arrival of this solar wind structure, ground magnetograms indicate that a very intense magnetic storm started to develop at about 8 UT and reached its minimum Dst ($<$ -450 nT) around 18 UT, then Dst recovered gradually until early November 21. During this storm, Geotail traversed the magnetotail at R ~ 9-12 Re from dusk to dawn through the midnight sector at ~ 17 UT on November 20 and observed the convection electric field in the near-Earth plasma sheet for the storm main phase and early recovery phase. The electric field in the plasma sheet during the main phase shows large fluctuations with amplitudes of several mV/m, implying the highly turbulent characteristics of the tail electric field in a wide range of local time. Aside from its large deviation, the average intensity of the duskward electric field is ~ 0.6 mV/m, which is not so different in magnitude from those observed during other moderate level storms (~ 0.3-0.6 mV/m). The observed tail electric field is compared with those calculated with some empirical ionospheric electric field models as well as that estimated with the polarcap potential drop actually observed simultaneously by the DMSP satellites. It is shown that the model electric fields calculated with the Boyle model and Weimer model both tend to overestimate the average storm-time intensity of the tail electric field by a factor of 1.5-3 during the main phase. On the other hand, the polarcap potential obtained by DMSP gives a better estimate for the tail electric field during this intense storm.
DE: 2700 MAGNETOSPHERIC PHYSICS
DE: 2712 Electric fields (2411)
DE: 2731 Magnetosphere--outer
DE: 2760 Plasma convection
DE: 2788 Storms and substorms
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting